JPS61277442A - Heat-resistant resin laminated board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a heat-resistant resin laminate that is widely used in electrical parts, mechanical parts, and the like.

[Conventional technology]

Generally, laminates are made by impregnating a base material such as glass cloth with synthetic resin such as phenol resin to create a resin-impregnated base material.
After this is dried and made into a prepreg, a predetermined number of prepregs are stacked and sandwiched between stainless steel head plates, and then placed between hot plates for heating and pressing (laminated molding). This type of laminate is widely used for electrical parts, mechanical parts, reinforcing materials, heat insulating materials, and the like. Particularly recently, in the field of electrical components, progress has been made toward smaller size, lighter weight, higher performance, and higher density, and the laminates used for these applications are also required to have improved characteristics, especially improved heat resistance.

In response to such demands for improved heat resistance of laminates, it has been considered to use aromatic polyimide, which has the highest heat resistance among engineering plastics, as the impregnating resin for the resin-impregnated base material. However, since aromatic polyimide is insoluble and infusible and has no melting point, the resin does not soften or melt when laminated and molded with an aromatic polyimide-impregnated base material. Not fused and integrated. For this reason, aromatic polyimide itself cannot be used as an impregnating resin for a resin-impregnated base material.
A laminate is manufactured by impregnating a base material with polyamic acid, which is a precursor of polyimide, to produce a polyamic acid-impregnated base material, and stacking and molding a plurality of these. However, during lamination molding of the polyamic acid-impregnated base material as described above, heating dehydration, ring-closing imidization of the impregnated polyamic acid occurs, and water is produced as a by-product. A major problem has arisen in that these particles remain and cause voids and the like.

[Problem that the invention seeks to solve]

As described above, according to the method of manufacturing a laminate by manufacturing a polyamic acid-impregnated base material and stacking and laminating a plurality of these, a polyimide resin laminate can be obtained.
It is possible to produce laminates with high heat resistance. However, a serious problem has arisen in that water, which is a by-product during dehydration and ring-closing imidization of polyamic acid, remains in the laminate, causing voids, etc., and is still not satisfactory.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide a heat-resistant resin laminate that does not cause problems such as voids.

[Means for solving problems]

In order to achieve the above object, the heat-resistant resin laminate of the present invention is a heat-resistant resin laminate formed by laminating a plurality of heat-resistant resin-impregnated base materials, the heat-resistant resin comprising:
Mainly consisting of a repeating unit represented by the following general formula (1),
The main component is an aromatic polyimide resin that can be heat-sealed as a continuous film under pressure.

Here, the term "main body" or "main component" includes the case where the whole is composed of only the main body or main component.

In order to solve the above-mentioned problems with polyimide resin laminates, the present inventors have conducted research focusing on thermoplasticization of aromatic polyimide, and as a result, they have discovered that aromatic tetracarboxylic acid, which is the starting material for aromatic polyimide, When a specific acid dianhydride is used as the dianhydride and this is combined with a specific aromatic diamino compound, an aromatic polyimide that does not exhibit a clear melting point but can be thermally fused in a continuous film state by pressure heating is produced. They discovered that if this was used as an impregnating resin for a resin-impregnated base material, a polyimide resin laminate could be obtained without passing through polyamic acid, and this invention was achieved. .

The aromatic polyimide resin that is heat-sealable under pressure and used in the heat-resistant resin laminate of the present invention can be obtained by reacting a specific aromatic tetracarboxylic dianhydride with a specific aromatic diamino compound. It will be done.

Examples of the above-mentioned specific aromatic tetracarboxylic dianhydrides include 3,3°,4,4'-biphenyltetracarboxylic dianhydride and derivatives thereof such as acid halides, diesters, and monoesters. These compounds may be used alone or in combination of two or more without any problem.

Note that, if necessary, other tetracarboxylic dianhydrides other than the above-mentioned aromatic tetracarboxylic dianhydrides can be used in place of a part of the above-mentioned aromatic tetracarboxylic dianhydrides. .

However, the use of large amounts of this type of tetracarboxylic dianhydride and other tetracarboxylic dianhydrides impairs the heat fusion properties of the aromatic polyimide resin, so the amount used is limited to 30 moles of the aromatic tetracarboxylic dianhydride. The amount of substitution should be limited to up to %.

Examples of the other tetracarboxylic dianhydrides include pyromellitic dianhydride, 3.3', 4.4'
-benzophenonetetracarboxylic dianhydride, 3.3
', 4,4'-biphenyltetracarboxylic dianhydride, 2.3,6,7-naphthalenetetracarboxylic dianhydride, and derivatives thereof such as acid halides; There is no problem in using a mixture of two or more types of anhydrides.

The specific aromatic diamino compound to be reacted with the specific aromatic tetracarboxylic dianhydride is an aromatic diamino compound represented by the following general formula (2) [X is the same as formula (1)] Examples include compounds.

Representative examples of the above-mentioned aromatic diamino compounds are as follows. 3,3′-diaminodiphenyl ether, 3,3′-diaminodiphenyl sulfone, 3.3
Examples include '-diaminodiphenylmethane, 3,3''-diaminobenzophenone, 3.3°-diaminodiphenyl sulfide, etc. These may be used alone or in combination.

Note that, if necessary, other diamino compounds can be used in place of a part of the above-mentioned specific aromatic diamino compounds. However, since the use of a large amount of this type of diamino compound deteriorates the heat fusion properties of the aromatic polyimide resin, the amount used should be limited to a substitution amount of up to 30 mol %.

The other aromatic diamino compounds mentioned above include p-phenylenediamine, m-phenylenediamine, 4,4°-
Diaminodiphenyl ether, 3.4°-diaminodiphenyl ether, 4.4°-diaminodiphenyl sulfone, 4.4°-diaminodiphenylmethane, 4.4°
-diaminodiphenylsulfide, 1,4-bis(4
-aminophenoxy)benzene, 4.4" -bis(4
-aminophenoxy)diphenyl, 4,4'-bis(4
Examples thereof include -aminophenoxy)diphenylsulfone, 2.2-bis(4,(4-aminophenoxy)phenyl)propane, and 2.2-bis(4-(4-aminophenoxy)phenyl)hexafluoropropane. These can also be used alone or in combination.

This invention manufactures a heat-resistant resin laminate using the heat-sealable polyimide resin as described above. There are the following two methods.

The first method is to make a polyimide precursor solution by reacting the aromatic tetracarboxylic dianhydride and an aromatic diamino compound in an organic polar solvent solution, and impregnate the base material with this solution as it is. The second method involves synthesizing a solvent-soluble aromatic polyimide resin in advance via a polyimide precursor, This is a method of manufacturing an aromatic polyimide resin-impregnated base material by impregnating the base material with an organic polar solvent solution of aromatic polyimide resin. To explain in more detail, the first method involves reacting an aromatic tetracarboxylic dianhydride and an aromatic diamino compound at a temperature of 0 to 90°C for 1 to 24 hours in an approximately equimolar polar solvent. The synthesized polyimide precursor can be obtained as an organic polar solvent solution), and if necessary, the solution viscosity can be adjusted by appropriately diluting it with an organic solvent for dilution or heating it. The base material is impregnated with the solvent solution of the polyimide precursor by a conventional method such as immersing the base material in this solution or using a one-drop spray method. Next, add this to 50~2
After pre-drying at a temperature of 50°C for 5 minutes to 2 hours, it is finally heated at 250 to 400°C for 5 minutes to 6 hours to complete the removal of the solvent or imidization, producing an aromatic polyimide resin-impregnated base material. do. In this case, the logarithmic viscosity of the polyimide precursor (the obtained polyimide precursor solution is
0-5g/100mj in 2-pyrrolidone! (measured at 30°C) is preferably set within the range of 0.1 to 5.0. More preferably, it is within the range of 0.3 to 3.0. When the above-mentioned logarithmic viscosity is less than 0.1, the mechanical strength of the obtained polyimide resin becomes low;
．． This is because if it exceeds 0, the solution viscosity becomes too high and impregnation workability etc. deteriorate. In addition, when impregnating the base material with the polyimide precursor solution, it is better to impregnate the base material in several steps rather than impregnating the base material with a predetermined amount of solution in one impregnation operation to avoid air bubbles remaining inside. In addition, the impregnation between the fibers of the base material is improved, so that good results can be obtained. The amount of resin in the aromatic polyimide resin-impregnated base material obtained as described above (weight of attached resin/weight of resin-impregnated base material x 100) is 20 to 50% (weight, same below)
, is preferably within the range of 25 to 40%, and for the above substrate-impregnated aromatic polyimide, the logarithmic viscosity (measured at 30°C at a concentration of 0.5 g/100 ml in concentrated sulfuric acid)
Setting the value within the range of 0.5 to 2.0 brings about good results.

Here, the logarithmic viscosity is calculated by the following formula, and the falling time in the formula is measured by a capillary viscometer.

It is known that this logarithmic viscosity is directly related to the molecular weight of the polymer.

The second method is a method in which the base material is not impregnated with a polyimide precursor solution, but is directly impregnated with a polyimide resin solution, and the aromatic tetracarboxylic dianhydride and aromatic diamino compound are A polyimide precursor solution is prepared by reacting in a solvent solution, and this is
A polyimide solvent solution is prepared by heating the polyimide precursor at a temperature of about 200° C. for 2 to 7 hours to cause dehydration and ring closure and imidization. Then, as in the first method, this is diluted with a diluting solvent or heated to lower the viscosity and impregnated into the base material, and then heated at a temperature of 50 to 250°C.
After pre-drying for 2 hours to 2 hours, the substrate is heated at 250 to 400° C. for 5 minutes to 6 hours to remove the solvent, thereby producing a polyimide resin-impregnated base material. When heating the polyimide precursor solution, water produced as a by-product during the imidization reaction is distilled out of the reaction system. This increases the reaction rate and brings about good results in producing high molecular weight polyimide. Good results can be obtained by setting the amount of resin and the intrinsic viscosity of the aromatic polyimide resin in the aromatic polyimide resin-impregnated base material thus obtained in the same manner as in the first method.

In addition, as the organic polar solvent as the polymerization solvent in the first and second methods, N-methyl-2-pyrrolidone, N,N-dimethylacetamide, N,N-dimethylformamide, dimethylsulfoxide, dimethylphosphoamide, Examples include m-cresol, p-cresol, p-chlorophenol, and the like. These may be used alone or in combination. Moreover, xylene, toluene, hexane, naphtha, etc. may be partially used in combination with the above organic polar solvent. Furthermore, the above polymerization solvent can be used as the diluent solvent in the first and second methods,
In addition, a general-purpose solvent with a low boiling point may be used within a range that does not adversely affect the impregnation process, such as the formation of precipitates. From the viewpoint of drying properties, it is advantageous to use such a low boiling point solvent in combination. Examples of the low boiling point solvent include toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, ethyl alcohol, methyl alcohol, and the like. These low boiling point solvents can also be used in combination of two or more types.

Further, in the first and second methods, it is preferable to add the phenol resin into the reaction vessel at the stage when the synthesis reaction of the polyimide precursor or polyimide is completed. In this way, when a phenol resin is added, the phenol resin will be present in the polyimide precursor solution or polyimide solution, so the phenol resin will melt when the base material is impregnated with the solution and pre-drying or main drying is performed. The polyimide precursor and polyimide are dissolved in the melt, the fluidity of the polyimide precursor and polyimide is improved, and the purpose of uniform impregnation can be achieved.

Furthermore, even when laminating and molding a plurality of aromatic polyimide-impregnated base materials obtained by the first and second methods, the phenol resin melts and dissolves the polyimide, so that uniform dispersion of the polyimide can be achieved. This also provides the effect of preventing air bubbles from remaining. In this case, if a large amount of phenol resin is used, the heat resistance of the resulting laminate will be reduced, so when using phenol resin, the amount is up to 10 parts by weight (hereinafter abbreviated as "parts") based on the polyimide. In particular, when heat resistance is required, the amount is up to 5 parts, and in these cases, it is preferable to use the epoxy resin in combination with the phenol resin, and use the epoxy resin as a crosslinking agent for the phenol resin.

The method of forming a laminate from the polyimide-impregnated base material obtained as described above involves stacking a predetermined number of polyimide-impregnated base materials, placing copper foil on one or both sides of the laminate as necessary, and then placing a copper foil on one or both sides of the laminate. Sandwiched between stainless steel mirror plates, temperature 200~
500℃, preferably 250-400℃, pressure 5-200℃
0 kg/cj, preferably 20-1000 kg/cy
This is a method of heating and pressurizing under the conditions of a for 5 minutes to 2 hours, preferably 10 minutes to 1 hour, to thermally fuse the polyimide in the plurality of polyimide resin-impregnated base materials and integrate the whole. As a result, the desired heat-resistant resin laminate is obtained.

In addition, as the above-mentioned base material, glass woven fabric, glass nonwoven fabric,
Examples include Kevlar woven fabric (manufactured by DuPont), carbon woven fabric, and mica sheet. Thickness of copper foil is 10~200mm
Examples include electrolytic copper foil or rolled copper foil with a thickness of .mu.m, and among them, one whose surface to be bonded to the laminate has been subjected to surface treatment such as oxidation treatment is preferable.

The heat-resistant resin laminate obtained as described above is formed by laminating a heat-resistant resin-impregnated base material whose main component is an aromatic polyimide resin (mainly consisting of repeating units represented by the general formula (11)). Because it is not constructed by laminating and molding base materials impregnated with a polyimide precursor solution as in the past, it does not contain water, etc., which is produced as a by-product during dehydration and ring-closing imidization of a polyimide precursor. Therefore, voids and the like caused by residual water, as in the past, do not occur at all.

Moreover, this laminate has extremely high heat resistance due to the heat resistance of the aromatic polyimide itself, which is the resin component, and also has excellent electrical properties such as 2m mechanical properties and chemical resistance. It is extremely useful not only in the field of parts, but also as mechanical parts, printed circuit boards, etc.

〔Effect of the invention〕

Since the heat-resistant resin laminate of the present invention is constructed as described above, there is no residual water or the like inside, and therefore, it is an extremely excellent product that does not cause problems such as voids.
Moreover, it has extremely excellent properties such as heat resistance. In particular, the aromatic polyimide resin, which is the main component of the heat-resistant resin, is heat-meltable, so the manufacturing process for the laminate is almost the same as the conventional manufacturing process in which thermosetting resin is used as the impregnating resin. , it also becomes possible to obtain the effect that conventional equipment can be used as is.

Next, examples will be described together with comparative examples.

[Example 1] In a '51 flask equipped with a stirrer and a thermometer, 3,
3°-diaminodiphenylsulfone (hereinafter referred to as “3.3°
-DDSJ) 248.3 g (1.0 mol)
Then, 2000 g of m-cresol was added and stirred to dissolve the diamine.

Next, 294 g (1.0 mol) of 3.3',4.4°-biphenyltetracarboxylic dianhydride (hereinafter abbreviated as rs-BPDAJ) was gradually added to this system, and the mixture was stirred for 3 hours to achieve a concentration of 21. A .3% polyimide precursor solution was obtained. During the above reaction, the system was cooled to keep the temperature below 30°C. The intrinsic viscosity (concentration of 0.5 g/100 mj! in m-cresol, measured at 30°C) of the obtained polyimide precursor was 0.75, and the solution viscosity was 250 poise (30
℃).

While continuing to stir this polyimide precursor solution,
The temperature was raised to 180° C. for 2 hours, and a heating reaction was carried out at a temperature of 180 to 190° C. for 2 hours to obtain a polyimide solution. During this time, water produced as a by-product was distilled out of the reaction system while flowing nitrogen gas.

The obtained polyimide solution was diluted to an appropriate viscosity with m-cresol and toluene, applied and impregnated onto a glass woven fabric by a dipping method, dried at 150°C for 30 molecules, then heated at 250°C for 30 minutes, then at 300°C. It was heat-treated for 30 minutes. Repeat this operation 5 times to create resin! 134
% polyimide resin impregnated base material was prepared.

Next, a predetermined number of these polyimide resin-impregnated base materials are stacked, placed between stainless steel hot plates that have been subjected to mold release treatment, and heated and pressed at a temperature of 360°C and a pressure of 80 kg/ad for 20 minutes to form a polyimide resin. - A glass woven laminate was obtained.

The physical properties of this laminate are shown in Table 1.

[Examples 2 to 4] Aromatic tetracarboxylic dianhydrides, aromatic diamines,
A laminate was produced in the same manner as in Example 1, except that the base material, solvent, etc. were used in the combinations shown in Table 1. Note that in Examples 2 and 3, a polyimide precursor solution was used, and in Examples 3 and 4, copper-clad laminates were produced.

The physical properties of these laminates are also shown in Table 1.

[Comparative Examples 1 to 4] Aromatic tetracarboxylic dianhydrides, aromatic diamines,
An attempt was made to produce a laminate in the same manner as in Example 1, except that the base material, solvent, etc. were used in the combinations shown in Table 1. The results are shown in Table 1.

Note that in Comparative Examples 1 and 4, polyimide precursor solutions were used.

In Table 1 below, BTDA is 3. 3'.

4.4'-benzophenonetetracarboxylic dianhydride, P? IDA is pimellitic dianhydride, 3,3”-
DDE is 3,3′-diaminodiphenyl ether, 3
．． 3'-DAB is 3,3"-diaminobenzophenone, 4,4°-DDE is 4,4"-diaminodiphenyl ether, 3,3"-DAM is 3,3"-diaminodiphenylmethane, and BAPP is 2.2 -Bis(4-
(4-aminophenoxy)phenyl]propane, DM
A c represents dimethylacetamide, PA represents a polyimide precursor solution, and PI represents a polyimide solution.

Margin below C)

Claims (1)

[Claims] (1) A heat-resistant resin laminate formed by laminating a plurality of heat-resistant resin-impregnated base materials, the heat-resistant resin comprising:
Mainly consisting of a repeating unit represented by the following general formula (1),
A heat-resistant resin laminate, characterized in that its main component is an aromatic polyimide resin that can be heat-sealed in a continuous film state under pressure. ▲There are mathematical formulas, chemical formulas, tables, etc.▼...(1) [In the above formula (1), X is O, S, SO_2, CH
_2, CO, C(CH_3)_2 or C(CF_3)
It is _2. ]